The present invention relates to an elevator system in which information is transmitted and received by wireless transmission between an elevator control unit and terminals in an elevator car and on each of the floors serviced by the elevator system.
An elevator is operated in response to requests generated through operation of a hall call button placed at a landing entrance on each of the floors and a car call button (also called a destination button) located inside the elevator car, and the statuses of the hall call button on each of the floors and the car call button in the car are sequentially transmitted to an elevator control unit. Wire communication has been generally used for this type of transmission.
Use of a wireless system for information transmission between an elevator machine room and a car is proposed in Japanese Patent Application Laid-Open No. 6-227766, Japanese Patent Application Laid-Open No. 7-97152 and Japanese Patent Application Laid-Open No. 11-150505. Further, Japanese Patent Application Laid-Open No. 3-46979 discloses a system in which a control panel in an elevator machine room on a rooftop of a building and an indicator at a landing entrance on each floor are connected by a wireless communication line.
On the other hand, in technical fields other than those related to an elevator system, there is a technology that involves the use of a plurality of specified small power wireless transmitting/receiving units or very-weak radio wave transmitting/receiving units, by which information is transmitted not directly, but by relaying the information between the units. Such technologies are disclosed in Japanese Patent Application Laid-Open No. 5-292577, Japanese Patent Application Laid-Open No. 6-348999, Japanese Patent Application Laid-Open No. 9-66129 and Japanese Patent Application Laid-Open No. 9-205908.
The above-mentioned conventional technologies in the field of elevator system have not been widely used because it has been presumed that a wireless unit having a large output capacity needs to be used corresponding to the height of the building. Further, none of the known technologies is sufficient to reduce the number of elevator wires in the building serviced by the elevator system.
An object of the present invention is to provide an elevator system in which information can with certainty be transmitted between an elevator control unit and a car, a counterweight or a landing entrance on each floor, even if wireless transmitting/receiving units having a comparatively narrow communicable range are employed.
In a preferred embodiment of the present invention, wireless units for transmitting/receiving very weak radio waves are individually incorporated in an elevator control unit and a car terminal or floor terminals. The wireless transmitting unit on the terminal on the sending side transmits a very weak radio wave toward a final receiving side (final destination), including transmission information. One of the terminals located near the terminal on the sending side, which receives the radio wave, transmits a radio wave including the same information toward another of the terminals located within a communicable range. After that, the above-described process is repeated until the information is received at the final destination. In communicating with the terminal in the car, the terminals to be used as relay stations are selected based on car positional information at the present time to perform the relay transmission.
By the use of wireless transmission in which information is relayed using a terminal within a communicable range, it is possible to communicate between a sending side and a receiving side which are too far apart to directly communicate from one to the other, and in this way, it is possible to carry out the sending and receiving of information in an elevator system using wireless transmitting/receiving units having a relatively narrow communication range.